Information
-
Patent Grant
-
6443557
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Patent Number
6,443,557
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Date Filed
Friday, October 29, 199924 years ago
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Date Issued
Tuesday, September 3, 200221 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 347 8
- 347 46
- 347 47
- 347 71
- 347 54
- 347 63
- 347 68
- 347 87
- 346 11
- 428 131
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International Classifications
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Abstract
A carrier frame having an aperture and a nozzle plate disposed on the carrier frame and positioned over the aperture is described. The nozzle plate has at least one nozzle formed between opposing surfaces of the nozzle plate. The carrier frame and the nozzle plate are made from materials having dissimilar thermal expansion coefficients such that the carrier frame has a thermal expansion coefficient that is less than the thermal expansion coefficient of the nozzle plate. The nozzle plate is staked to the carrier frame and then baked so that the nozzle plate shrinks during the baking process thereby becoming taught and under a state of tensile stress. The nozzle is formed in the nozzle plate after the baking process by laser ablation, for example. The nozzle thus formed has a true bore due to the taught nozzle plate and the opposed surfaces of the nozzle plate being parallel to each other. Consequently, a nozzle camber angle measured relative to a nozzle axis and defined by an angular displacement between a center point of symmetry on an input side of the nozzle and a center point of symmetry on an output side of the nozzle is coaxially aligned with the nozzle axis. By eliminating dimples in the nozzle plate, the nozzle has sidewall surfaces that are symmetric with respect to the nozzle axis thereby defining a nozzle with a true bore. An ink drop injected into the nozzle by an ink jet printhead mounted to the nozzle plate and having a firing chamber in fluid communication with the nozzle will exit the nozzle in a direction that is aligned with the nozzle camber angle such that the drop directionality of the ink drop is improved by true bore of the nozzle.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to a chip carrier having a taught and planar nozzle plate with a nozzle having a true bore formed therein. More specifically, the present invention relates to a chip carrier having a taught and planar nozzle plate with a nozzle that has a nozzle camber angle that is aligned with a firing axis of a thermal ink jet resistor and a nozzle axis of the nozzle so that fluid injected into the nozzle exits in a direction along the nozzle axis.
Articles and publications set forth herein are presented for the information contained therein: none of the information is admitted to be statutory “prior art” and we reserve the right to establish prior inventorship with respect to any such information.
Ink jet drop directionality can be improved by providing a nozzle plate having a nozzle with a true bore. A true bore is simply a nozzle in the nozzle plate that has sidewall surfaces that are uniform and symmetric about an axis of the nozzle. By way of analogy, an example of a true bore is the barrel of a cannon. The cannon has barrel sidewalls that are symmetric with respect to a bore axis of the canon. Thus, a projectile propelled thru the barrel exits the barrel with a trajectory that is along the bore axis. On the other hand, if the barrel has sidewalls that are not symmetric with respect to the bore axis then the barrel will not have a true bore (i.e. a crooked barrel) and the projectile will exit the barrel with a trajectory that is not along the bore axis. Consequently, the projectile will not strike its desired impact point. Therefore, lack of a true bore results in inaccuracies in the trajectory of the projectile.
Similarly, for a thermal ink jet printhead, an ink drop ejected from a firing chamber of the printhead and into a nozzle that does not have a true bore results in the ink drop exiting the nozzle with a trajectory that is not along the nozzle axis. As a result, the ink drop trajectory will deviate from a desired impact point on a print media such as a sheet of paper positioned opposite the nozzle.
In a typical thermal ink jet printhead, a semiconductor substrate is bonded to an orifice plate (a nozzle plate) using a barrier layer. A firing chamber is formed by the substrate and the barrier layer. A firing element such as a thermal ink jet resistor is disposed in the firing chamber and a firing axis of the firing element is aligned with a nozzle axis of a nozzle formed in the nozzle plate. The barrier layer seals the firing chamber to the nozzle plate so that the firing chamber is in fluid communication with the nozzle. A fluid channel communicates ink from an ink reservoir to the firing chamber. The substrate includes a signal line that electrically communicates a signal from a control unit (which may be connected to a source of printing data) to the firing element. A signal communicated to the firing element causes ink disposed on the element to be heated and subsequently ejected from the firing chamber and into the nozzle. The ink drop exits the nozzle with a trajectory that is determined by the symmetry of the nozzle. If the nozzle has a true bore, then the trajectory of the ink drop is substantially along an axis of the nozzle. Conversely, if the nozzle does not have a true bore then the trajectory of the ink drop deviates from the nozzle axis. By way of example, a general discussion of thermal ink jet printheads, nozzle plates, and thermal ink jet printhead construction can be found in the Hewlett-Packard Journal, Volume 39, No. 5, October 1998, Volume 39, No. 4, August 1998, and Volume 36, No. 5, May 1985.
Prior attempts to create a nozzle plate with a true bore nozzle have been frustrated by deformities in the nozzle plate. Typically, the nozzle plate is a thin film of flexible material such as a polyimide film, for example. The nozzle plate has opposed input and output surfaces thru which an orifice (a nozzle) is formed. The nozzle plate is then bonded to the substrate in a process called staking where the barrier layer is applied to the substrate and then heat and pressure are applied to attach the input surface of the nozzle plate to the barrier layer. The completed assembly is then baked at a high temperature to cure the barrier layer.
The deformities in the nozzle plate aries due to compressive buckling of the nozzle plate caused by the staking and baking process. Resulting is dimpling of the nozzle plate. The dimples in the nozzle plate resemble the peaks and troughs of ocean waves and can be sinusoidal in appearance. Therefore, the input and output surfaces of the nozzle plate deviate from planarity such that a nozzle formed in the nozzle plate will not have sidewall surfaces that are symmetric about the nozzle axis.
Moreover, the nozzle has openings on the input and output surfaces. A center point of symmetry on an input side of the nozzle is not coaxially aligned with a center point of symmetry on an output side of the nozzle. Resulting is misalignment between the input and output sides of the nozzle with respect to the nozzle axis. Because of the misalignment, sidewall surfaces of the nozzle are not symmetric with the nozzle axis, therefore, the nozzle does not have a true bore.
Referring to
FIG. 1
, there is illustrated a dimpled nozzle plate
101
having an input surface
103
disposed opposite an output surface
105
. The opposed surfaces have a generally sinusoidal contour; however, the nozzle plate can have other surface deformations that can result in a nozzle that does not have a true bore. A nozzle
107
is formed in the nozzle plate
101
by sidewall surfaces
109
that extend between the input surface
103
and the output surface
105
. Those skilled in the ink jet printer art commonly refer to the nozzle plate
101
as an orifice plate and the nozzle
107
as an orifice; however the term nozzle plate and nozzle will be used hereinafter.
A center point of symmetry
111
on an input side
113
(the side from which ink or some other fluid is injected into the nozzle) of the nozzle
107
is not coaxially aligned with a center point of symmetry
115
on an output side
117
of the nozzle
107
. A nozzle axis
119
is referenced to the center point of symmetry
111
on the input side
113
. Deviation from coaxial alignment between the center points of symmetry is measured in angular degrees by a nozzle camber angle (NCA)
123
. The NCA
123
is measured between the nozzle axis
119
and a camber line
121
extending thru the center points of symmetry
111
and
115
respectively. An ink drop or other fluid (not shown) entering the input side
113
of the nozzle
107
will exit the output side
117
with a trajectory that substantially matches the NCA
123
(i.e. the fluid trajectory is along the camber line
121
). Because of the dimple in the nozzle plate
101
, the sidewall surfaces
109
are not symmetric with respect to the nozzle axis
119
as will be discussed below.
Consequently, the ink drop, for example, will not strike a desired impact point on a print media.
FIG. 2
is an illustration of the effect the dimpled nozzle plate
101
of
FIG. 1
has on ink drop directionality. A print surface
133
of a print media
131
is shown with a desired impact point X and an actual impact point X′ displaced a lateral distance from the desired impact point X. The print media
131
can be a sheet of paper, for example. As can be seen in
FIG. 2
the actual impact point X′ coincides with the camber line
121
and is caused by the ink drop (not shown) having a trajectory that substantially matches the NCA
123
.
Additionally, the sidewall surfaces
109
of the nozzle
107
are not symmetric about the nozzle axis
119
due to the dimpling of the nozzle plate. Lack of symmetry between the nozzle axis
119
and the sidewall surfaces
109
is shown by unequal length radius lines d
1
and d
1
′, d
2
and d
2
′, and d
3
and d
3
′ that extend between the nozzle axis
119
and the sidewall surfaces
109
. Essentially, the nozzle
107
does not have a true bore due to lack of symmetry between the sidewall surfaces
109
and the nozzle axis
119
.
Accordingly, the center point of symmetry
115
on the output side
117
is not coaxially aligned with the nozzle axis
119
as shown in
FIG. 2
a
. The center point of symmetry
115
on the output side
117
is illustrated as a cross “+” and the nozzle axis
119
is illustrated as a dot “•” in
FIG. 2
a.
Ideally, however, it is desirable to have the center point of symmetry
115
on the output side
117
to be coaxially aligned with the nozzle axis
119
as shown in
FIGS. 3 and 3
a
. As can be seen in
FIG. 3
, the center point of symmetry
115
on the output side
117
is coaxially aligned with the center point of symmetry
111
on the input side
113
so that the camber line
121
is coaxially aligned with the nozzle axis
119
and the NCA
123
is substantially 0.0 degrees. Resulting is an ink drop (not shown) that strikes the print side
133
of the print media
131
at the desired impact point X. Essentially the true bore of the nozzle
107
results in the camber line
121
coinciding with the desired impact point X.
Moreover, the sidewall surfaces
109
of the nozzle
107
are symmetrically disposed about the nozzle axis
119
such that the radius lines d
1
and d
1
′, d
2
and d
2
′, and d
3
and d
3
′ are of equal length. Therefore, as can be seen in
FIG. 3
a
, the center point of symmetry
115
on the output side
117
is coaxially aligned with the nozzle axis
119
. Another way of viewing
FIGS. 3 and 3
a
is that coaxial alignment of the center point of symmetry
115
on the output side
117
with the center point of symmetry
113
on the input side
113
results in coaxial alignment of the NCA
123
with the nozzle axis
119
, whereby the nozzle
107
has a true bore.
FIG. 4
is an illustration of the dimpled nozzle plate
101
coupled to a substrate
300
that defines an ink jet print head
301
mounted to the input side
103
of the nozzle plate
101
by a barrier layer
303
. A firing chamber
305
is formed in the barrier layer
303
and the substrate
300
. The barrier layer
303
seals the firing chamber
305
to the nozzle plate
101
so that the firing chamber
305
is in fluid communication with the nozzle
107
. A fluid channel
307
supplies ink (not shown) to the firing chamber
305
from an ink reservoir (not shown). The firing chamber
305
includes a firing element
309
disposed in the firing chamber
305
and having a firing axis
311
that is aligned with the nozzle axis
119
. A signal line
315
connects the firing element
309
to a control unit (not shown) that electrically communicates a signal to the firing element
309
. Those skilled in the ink jet printer art commonly refer to the firing element
309
as a thermal ink jet resistor; however, the term firing element will be used hereinafter.
As mentioned previously, the firing element
309
is operative to heat ink supplied to the firing chamber
305
into an ink bubble
313
that is ejected from the firing chamber
305
along the firing axis
311
. The ink bubble
313
enters the input side
113
of the nozzle
107
and exits the nozzle
107
thru the output side
117
. As can be seen in
FIG. 4
, due to dimpling of the nozzle plate
101
the NCA
123
is not aligned with the nozzle axis
119
, therefore, the ink drop
213
will have a trajectory that substantially matches the NCA
123
. Resulting is inaccuracy in the directionality of the ink drop
313
such that the ink drop
313
travels along the camber line
121
rather than the nozzle axis
119
.
Although
FIG. 4
shows dimple on the output surface
105
, the input surface
103
may also be dimpled. Dimpling of the input surface
103
can cause additional problems, namely, a defective fluid seal between printhead
301
and the nozzle plate
101
caused by voids in the barrier layer
303
. The ink drop
313
can be diverted into those voids resulting in reduced ink drop output, a clogged nozzle, or a defective firing chamber. Accordingly, it is important that both the input surface
103
and output surface
105
be planar surfaces that are parallel to each other.
Therefore, there is a need to overcome the disadvantages associated with dimpling of the nozzle plate and the resulting inaccuracies in ink drop directionality. A nozzle plate that is taught and has planar input and output surfaces can eliminate the dimpling of the nozzle plate. Furthermore, the planar surfaces of the nozzle plate result in the input and output surfaces being parallel to each other. The taught nozzle plate provides a surface thru which a true bore nozzle can be formed and provides a flat and stable surface for mounting the ink jet printhead to the nozzle plate.
Moreover, there is a need for a nozzle plate that remains taught and maintains planarity of the input and output surfaces after the nozzle plate has been subjected to the staking and baking process.
Another disadvantage to mounting the ink jet printhead to the nozzle plate is that the signal lines in the printhead must be connected to a control unit that communicates print signals to the printhead. In a typical application, the nozzle plate includes electrically conductive traces that are disposed on the input or output surfaces. The traces connect to a bonding pad or similar structure on the printhead and are operative to communicate signals from the control unit to the signal lines connected to the firing element. The traces can be patterned on the nozzle plate using PC board lithography techniques, for example. Alternatively, wire bonds can be used to facilitate connection of the control unit to the signal lines. One or more apertures are formed in the nozzle plate to facilitate routing of the trace or the wire bond to the printhead.
Thus, the nozzle plate may need to be made larger in order to accommodate the traces and apertures. It is more difficult to prevent surface irregularities in a nozzle plate that serves dual roles as both a fluidic device and an electronic device, mainly due to the larger area of the nozzle plate and defects introduced by processing steps related to making the necessary electrical connections to the printhead.
Therefore, there is a need to overcome the disadvantages associated with combining the fluidic and electronic functions in the nozzle plate. A carrier frame operative to support the nozzle plate so that the printhead can be mounted to the nozzle plate without electrical connections can decouple the fluidic and electronic functions of the nozzle plate. A separate flexible circuit material can be connected to the carrier frame and can communicate electrical signals between the control unit and the printhead. Separation of the electronic and fluidic functions has the added advantage of allowing the nozzle plate and the flex circuit to be made from different materials.
SUMMARY OF THE INVENTION
The problems and limitations associated with dimpling of the nozzle plate are addressed by various aspects of the present invention. Dimpling of the nozzle plate is eliminated by disposing the nozzle plate on a carrier frame and staking and baking the nozzle plate to the carrier frame so that the nozzle plate is taught, planar, and has input and output surfaces that are parallel to each other. After the staking and baking process the nozzle plate remains taught and planar so that nozzles formed in the nozzle plate have a true bore. The carrier frame and the nozzle plate define a chip carrier. An ink jet printhead is mounted to an input surface of the nozzle plate.
Additionally, the problems associated with a nozzle plate that performs both fluidic and electronic functions is solved by using the above mentioned chip carrier and including an electrically conductive bonding pad on the carrier frame. A separate flex circuit that carries electrically conductive traces is mounted to the carrier frame and the traces are connected to the bonding pads on the carrier frame. Signal lines on an ink jet printhead mounted to the nozzle plate can be connected to the bonding pads thereby decoupling the fluidic function of the nozzle plate from the electronic function of the traces. The flex circuit and the nozzle plate need not be made from the same material. For instance, the nozzle plate can be made from a material capable of forming a taught nozzle plate and the flex circuit can be made from a material that is well suited for patterning and etching of signal lines.
Broadly, the present invention provides a chip carrier that includes a carrier frame having opposed shelf and base surfaces, a frame aperture extending between the shelf and base surfaces, and a nozzle plate having opposed input and output surfaces. A nozzle is formed by sidewall surfaces that extend between the opposed surfaces. The nozzle plate is fixedly disposed on the shelf surface of the carrier frame with the input surface adjacent to the frame aperture. The nozzle plate is characterized by being disposed on the shelf surface in a state of tensile stress so that the input and output surfaces are taught, planar, and parallel to each other.
The tensile stress on the nozzle plate is operative to symmetrically dispose the sidewall surfaces of the nozzle with respect to a nozzle axis so that the nozzle has a true bore and a nozzle camber angle is coaxially aligned with a nozzle axis. A fluid injected into the nozzle exits the nozzle with a trajectory that substantially matches the nozzle camber angle.
In one embodiment of the present invention, the nozzle plate is made from a first material that has a first thermal expansion coefficient and the carrier frame is made from a second material that has a second thermal expansion coefficient. The second thermal expansion coefficient is less than the first thermal expansion coefficient so that the dissimilarity between the first and second thermal expansion coefficients operates to generate the tensile stress on the nozzle plate.
In another embodiment of the present invention, the nozzle has converging sidewall surfaces that converge in a direction toward an output side of the nozzle. In one embodiment the converging sidewall surfaces are arcuate in shape.
In one embodiment of the present invention, the nozzle plate is fixedly .connected to the shelf surface of the carrier frame by an adhesive disposed between the shelf surface and the input surface of the nozzle plate.
In another embodiment of the present invention, the shelf surface includes a raised portion defining a lip that extends outward of the shelf surface and terminates in a planar upper surface. The input surface of the nozzle plate is disposed on the upper surface of the lip and the nozzle plate is fixedly connected to the shelf surface by an adhesive disposed between the shelf surface and the input surface of the nozzle plate. The lip provides a flat reference plane upon which to mount the nozzle plate so that planarity of the nozzle plate is not compromised by non-uniform thickness of the adhesive.
In one embodiment of the present invention, a barrier layer mounts an ink jet printhead to the input surface of the nozzle plate. A firing chamber of the printhead is aligned with and is in fluid communication with a nozzle in the nozzle plate. The firing chamber includes a firing element that has a firing axis that is coaxially aligned with the nozzle axis.
In another embodiment of the present invention, the nozzle plate includes at least one feed-thru aperture for routing an interconnect line from a bonding pad disposed on the carrier frame to a signal line on the ink jet printhead.
In one embodiment of the present invention, the chip carrier is mounted to a flex circuit that includes an electrically conductive trace. The trace connects to a bonding pad disposed on the carrier frame. The bond pad is in electrical communication with the signal line in the ink jet printhead. The trace is operative to communicate a signal from the control unit to the signal line.
Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a cross-sectional view of a dimpled nozzle plate and a nozzle that does not have a true bore.
FIG. 2
is a cross-sectional view illustrating the effect the dimpled nozzle plate of
FIG. 1
has on ink drop directionality and on symmetry of the nozzle sidewall surfaces with respects to the nozzle axis.
FIG. 2
a
is a top view of the nozzle of FIG.
2
and illustrates misalignment between the input and output sides of the nozzle caused by the dimpled nozzle plate of FIG.
1
.
FIG. 3
is a cross-sectional view illustrating a nozzle having a true bore and sidewall surfaces that are symmetric about the nozzle axis according to the present invention.
FIG. 3
a
top view of the nozzle of FIG.
3
and illustrates alignment of the center points of symmetry on the input and output sides of the nozzle according to the present invention.
FIG. 4
is a cross-sectional view of an ink jet printhead mounted to the input surface of a dimpled nozzle plate.
FIG. 5
is a cross-sectional view of an ink jet printhead mounted to the input surface of a taught and planar nozzle plate according to the present invention.
FIG. 6
is a top plan view of a carrier frame according to the present invention.
FIG. 7
is a bottom plan view of a base surface of the carrier frame of
FIG. 6
according to the present invention.
FIG. 8
is a cross-sectional view of the carrier frame of
FIG. 6
according to the present invention.
FIG. 9
is a cross-sectional view of the carrier frame of
FIG. 6
having a taught nozzle plate disposed on a shelf surface of the carrier frame according to the present invention.
FIG. 10
is a top plan view of the carrier frame of
FIG. 6
having a taught nozzle plate fixedly connected to opposing sides of the shelf surface.
FIG. 11
is a top plan view of a carrier frame having a lip disposed on the shelf surface thereof according to the present invention.
FIG. 12
is a cross-sectional view of the carrier frame and the lip of
FIG. 11
according to the present invention.
FIG. 13
is a cross-sectional view of the carrier frame of
FIG. 12
having a taught nozzle plate disposed on a planar upper surface of the lip and fixedly connected to the shelf surface according to the present invention.
FIG. 14
is a top plan view of a front surface of a flex circuit having a nozzle aperture therein according to the present invention.
FIG. 15
is a bottom plan view illustrating electrically conductive traces disposed on a bottom surface of the flex circuit of
FIG. 14
according to the present invention.
FIG. 16
is a top plan view of a carrier frame having bonding pads and a nozzle plate disposed thereon according to the present invention.
FIG. 17
is a cross-sectional view of the carrier frame of
FIG. 16
mounted to the bottom side of the flex circuit of
FIG. 15
with the electrically conductive traces connected to the bonding pads according to the present invention.
FIG. 18
is a cross-sectional view of a carrier frame mounted to the bottom side of a flex circuit and having a nozzle plate disposed on a lip portion according to the present invention.
FIG. 19
is a cross-sectional view of the carrier frame and flex circuit of
FIG. 17
with an ink jet printhead mounted to the nozzle plate and bonding wires connecting signal lines on the printhead to the bonding pads according to the present invention.
FIG. 20
is a side plan view of a flex circuit having a feed-thru aperture for routing of bonding wires to a signal line according to the present invention.
FIG. 21
is a top plan view of the feed-thru aperture and bonding pads of
FIG. 20
according to the present invention.
FIG. 22
is a top plan view of a nozzle plate having a feed-thru aperture and an electrically conductive trace according to the present invention.
FIG. 23
is a cross-sectional view illustrating routing of the trace of
FIG. 22
to a signal line of an ink jet printhead according to the present invention.
FIG. 24
is a top plan view of a nozzle plate having a feed-thru aperture and a carrier frame having a bonding pad thereon according to the present invention.
FIG. 25
is a cross-sectional view illustrating routing of a bonding wire through the feed-thru aperture of
FIG. 24
according to the present invention.
FIG. 26
is a ross-sectional view of the chip carrier of
FIG. 23
mounted to a print cartridge according to the present invention.
FIG. 27
is a side view of the chip carrier of
FIG. 19
mounted to a print cartridge according to the present invention.
FIG. 28
is a cross-sectional view of a nozzle plate with substantially vertical sidewall surfaces according to the present invention.
FIG. 29
is a cross-sectional view of a nozzle plate having a nozzle with sidewall surfaces that converge towards the output side of the nozzle according to the present invention.
FIG. 30
is a cross-sectional view of a nozzle plate having a nozzle with converging sidewall surfaces that are arcuate in shape according to the present invention.
FIG. 31
is a top plan view of the taught nozzle plate and ink jet printhead of FIG.
5
and illustrates coaxial alignment of the firing element with the true bore nozzle.
DETAILED DESCRIPTION
In the following detailed description and in the several figures of the drawings, like elements are identified with like reference numerals.
As shown in the drawings for purpose of illustration, the present invention is embodied in an a chip carrier that includes a carrier frame having opposed shelf and base surfaces and a frame aperture that extends between the shelf and base surfaces. A nozzle plate having opposed input and output surfaces is disposed on the shelf surface with the input surface positioned adjacent to the frame aperture. The nozzle plate is fixedly connected to at least two opposing sides of the shelf surface.
The nozzle plate is disposed on the shelf surface in a state of tensile stress so that the input and output surfaces of the nozzle plate are taught, planar, and parallel to each other. The tensile stress on the nozzle plate eliminates dimpling of the input and output surfaces. A nozzle is formed by sidewall surfaces that extend between the input and output surfaces. The nozzle has a nozzle camber angle that is measured relative to a nozzle axis. The nozzle camber angle is defined by an angular displacement between a center point of symmetry on an input side of the nozzle and a center point of symmetry on an output side of the nozzle.
The shelf surface of the carrier frame can include a raised portion defining a lip that extends outward of the shelf surface and terminates in a planar upper surface. The input surface of the nozzle plate can be disposed on the planar upper surface. The upper surface of the lip provides a flat reference plane for the nozzle plate whereby non-uniform thickness of an adhesive used to fixedly attach the input surface of the nozzle plate to the shelf surface does not compromise the planarity of the nozzle plate. As a result, nozzles formed in the nozzle plate maintain a true bore and drop directionality is improved.
The tensile stress on the nozzle plate is operative to symmetrically dispose the sidewall surfaces of the nozzle about the nozzle axis and to align the center points of symmetry of the input and output sides of the nozzle with the nozzle axis so that the nozzle camber angle is coaxially aligned with the nozzle axis and the nozzle camber angle is substantially 0.0 degrees.
In essence, the taught nozzle plate provides a planar surface through which a nozzle having a true bore can be formed. Thus, a fluid injected into the nozzle thru the input side of the nozzle will exit the output side of the nozzle with a fluid trajectory that substantially matches the nozzle camber angle.
Accordingly, the problems associated with dimpling of the nozzle plate are solved by the chip carrier of the present invention. The carrier frame provides a stable platform upon which the nozzle plate can be mounted. The tensile stress acting on the nozzle plate results in a planar and taught nozzle plate that remains taught and planar after the previously mentioned stake and bake process. A nozzle formed in the nozzle plate has sidewall surfaces that are symmetric about the nozzle axis thereby creating a true bore nozzle that improves the drop directionality of a fluid exiting the nozzle such as an ink drop, for example. Because the ink drop has a trajectory that is along the nozzle axis, the ink drop will impact a print surface positioned opposite the nozzle with greater directional accuracy when compared to the ink drop directionality of a dimpled nozzle plate.
A flex circuit having opposed front and back surfaces and a nozzle aperture extending between the opposed surfaces can be used to mount the chip carrier of the present invention with the nozzle plate positioned in the nozzle aperture. A bonding pad disposed on the carrier frame and an electrically conductive trace disposed on the back surface can be used to decouple the fluidic function of the nozzle plate from the electronic function of communicating electrical signals to an ink jet printhead disposed on the input surface of the nozzle plate.
Additionally, by decoupling the electronic and fluidic functions, the chip carrier of the present invention can eliminate electronic traces that would normally be disposed on the output surface of the nozzle plate. Consequently, the output side of the nozzle plate can be positioned closer to a print media such as a piece of paper, for example. Ink drop directionality is further improved by reducing the distance between the nozzle plate and the print media because the ejected ink drop travels a shorter distance from the nozzle to the surface to be printed. Furthermore, by decoupling the electronic and fluidic functions, the nozzle plate and the flex circuit can be made from different materials as will be discussed below.
Referring to
FIGS. 6
,
7
, and
8
, the chip carrier of the present invention includes a carrier frame
203
having opposed shelf
205
and base
207
surfaces. The carrier frame
203
has a frame aperture
209
that extends between the opposed surfaces.
FIG. 7
is a bottom plan view of the carrier frame
203
showing the base surface
207
.
FIG. 8
is a cross sectional view of the carrier frame
203
showing the frame aperture
209
(shown in dashed lines) extending between the shelf surface
205
and the base surface
207
. Although the carrier frame
203
is illustrated as being rectangular in shape, the shape of the carrier frame is not limited to the rectangular shape thus illustrated.
Referring to
FIG. 9
, a chip carrier
201
of the present invention includes the carrier frame
203
as discussed above and a nozzle plate
211
. The nozzle plate
211
includes opposed input
213
and output
215
surfaces. At least one nozzle
217
is formed in the nozzle plate by sidewall surfaces
219
that extend between the input surface
213
and the output surface
215
. Although the nozzle plate
211
is shown having three nozzles, the nozzle plate
211
can have only one nozzle or a plurality of nozzles. Typically, a nozzle plate for an ink jet printhead (not shown) will have a plurality of nozzles arranged in an array pattern on the nozzle plate.
The nozzle plate
211
is disposed on the shelf surface
205
of the carrier frame
203
with the input surface
213
positioned adjacent to the frame aperture
209
. The nozzle plate
211
is fixedly connected to at least one pair of opposing sides
223
of the shelf surface
205
. The nozzle plate
211
can be fixedly connected to the shelf surface of the nozzle plate using an adhesive
227
, for example. The adhesive
227
is disposed between the shelf surface
205
and the input side
213
.
Referring to
FIG. 10
, the adhesive
227
can be applied to at least one pair of opposing sides of the shelf surface
205
of the carrier frame
203
. Therefore, one pair of opposing sides
223
can have the adhesive
227
disposed thereon. Alternatively, another pair of opposing sides
225
can have the adhesive
227
disposed thereon. On the other hand, the adhesive
227
can be disposed on both pairs of opposing sides
223
and
226
respectively so that the input surface
213
of the nozzle plate is fixedly connected to all four sides of the shelf surface
205
. The input side
213
of the nozzle plate
211
is positioned adjacent to the frame aperture
209
with the nozzle
217
disposed over the frame aperture
209
. A fluidic device such as an ink jet printhead (not shown), for example, can then be positioned in the frame aperture
209
and mounted to the input side
213
with a firing chamber of the device aligned with the nozzle
217
.
The nozzle plate
211
is permanently connected to the shelf surface of the carrier frame
203
by applying the adhesive
227
in a liquid state, then cross linking the adhesive
227
to form a solid. Next, heat and pressure are applied to the nozzle plate
211
and the carrier frame
203
, thereby staking the nozzle plate
211
to the carrier frame
203
. Following the staking step, the adhesive
227
is cured by baking the chip carrier
201
at a high temperature to dry out any moisture in the nozzle plate
211
and to shrink the nozzle plate
211
. The shrinking results in a taught nozzle plate
211
that is planar (flat surface) and has parallel input
213
and output
215
surfaces. However, the carrier frame
203
does not shrink as much as the nozzle plate
211
. Consequently, the nozzle plate
211
is disposed on the shelf surface
205
in a state of tensile stress.
Adhesives such as RISTON™, VACREL™, and PARAD™, for example, can be used to fixedly attach the nozzle plate
211
to the shelf surface
205
.
The tensile stress results in the input
213
and output
215
surfaces of the nozzle plate
211
being taught (like the head of a drum). Moreover, the tensile stress acting on the nozzle plate
211
is operative to make the input
213
and output
215
surfaces planar and parallel to each other. Therefore, the aforementioned problems associated with dimpling of the nozzle plate are addressed by the chip carrier
201
of the present invention.
In one embodiment of the present invention as illustrated in
FIGS. 11
,
12
, and
13
, the shelf surface
205
of the carrier frame
203
includes a raised portion defining a lip
251
. The lip
251
extends outward of the shelf surface
205
and terminates in an planar upper surface
253
. Referring to
FIG. 13
, the input surface
213
of the nozzle plate
211
is disposed on the planar upper surface
253
of the lip
251
and the nozzle plate
211
is fixedly connected to the shelf surface
205
by an adhesive
257
.
The lip
251
provides a flat reference plane (the planar upper surface
253
) for mounting the nozzle plate
211
. By placing the reference plane for the nozzle plate
211
above the shelf surface
205
, non-uniform thickness of the adhesive
257
will not compromise the planarity of the nozzle plate
211
or its opposed surfaces.
For instance, in
FIG. 10
, if the input side
213
of the nozzle plate
211
is fixedly connected to the shelf surface
205
at the first pair of opposing sides
223
and the side on the left has a thicker layer of the adhesive
227
, then the nozzle plate
211
will have a slight tilt (slope) towards the side right side because the layer of adhesive
227
is thinner on the right side. A sloped nozzle plate defeats the goal of having a planar nozzle plate
211
.
Accordingly, the lip
251
of
FIG. 12
isolates that portion of the nozzle plate
211
that must be planar from the portion that is fixedly connected to the shelf surface
205
. Although
FIG. 11
illustrates the lip
251
encircling the frame aperture
209
, the lip
251
can be disposed on at least one pair of opposing sides of the shelf surface
205
. The staking and baking process described above can be used to fixedly connect the nozzle plate
211
to the carrier frame and to generate the tensile stress on the nozzle plate
211
.
In another embodiment of the present invention, the nozzle plate
211
is made from a first material having a first thermal expansion coefficient and the carrier frame
203
is made from a second material having a second thermal expansion coefficient. The second thermal expansion coefficient of the carrier frame
203
is less than the first thermal expansion coefficient of the nozzle plate
211
. The dissimilarity between the first and second thermal expansion coefficients is operative to generate the tensile stress on the nozzle plate
211
. As a result of the staking and baking process, as the chip carrier
201
cools off, the nozzle plate
211
shrinks at a higher rate than the carrier frame
203
due the carrier frame
203
be made from a material having a thermal expansion coefficient that is less than that of the nozzle plate
211
. Once the carrier frame
201
has completely cooled off, the nozzle plate
211
is disposed on the carrier frame
203
in tensile stress so that the opposed surfaces of the nozzle plate
211
are taught, planar, and parallel to each other.
In one embodiment of the present invention, the first thermal expansion coefficient for the nozzle plate
211
is in a range from about 12.00 ppm/°C. to about 25.00 ppm°C., and the second thermal expansion coefficient for the carrier frame
203
is in a range from about 3.00 ppm/°C. to about 11.00 ppm°C.
In another embodiment of the present invention, the first material for the nozzle plate
211
can be polyimide film, KAPTON™, UPILEX™, and APICAL™, for example. The second material for the carrier frame
203
can be ceramic, alumina, nickel-iron alloy, KOVAR™, and INVAR™, for example.
The above materials for the nozzle plate
211
can be laser ablated as will be discussed below, have good adhesion properties, and resist penetration by water. The above materials for the carrier frame
203
are known for their low thermal expansion coefficients, are rigid, stable, and resistant to ink corrosion.
The materials for the nozzle plate
211
and the carrier frame
203
should be selected so that dissimilarity between the thermal expansion coefficients of the materials results in tensile stress on the nozzle plate
211
. Moreover, for ink jet applications, the. materials for the nozzle plate
211
and the carrier frame
203
should be selected based on their resistence to the corrosive effects of ink. In general, corrosion and chemical attack by fluids used in conjunction with the chip carrier
201
of the present invention should be taken into consideration when selecting appropriate materials for the nozzle plate
211
and the carrier frame
203
.
In one embodiment of the present invention, the tensile stress on the nozzle plate
211
is in a range from about 6.50 Mpa to about 140.0 Mpa. The actual tensile stress acting on the nozzle plate
211
can vary with temperature. However, the above range represents the range of tensile stress at about room temperature.
Referring to
FIG. 5
, the nozzle
217
is illustrated in greater detail. The nozzle
217
includes a center point of symmetry
231
on an input side
233
of the nozzle
217
and a center point of symmetry
235
on an output side
237
of the nozzle
217
. A nozzle axis
241
(heavy dashed arrow) is referenced to the center point of symmetry
231
on the input side
233
and extends from the input side
233
thru the output side
237
. A nozzle camber angle
245
(NCA) is measured relative to the nozzle axis
241
and is defined by angular displacement between the center point of symmetry
231
on the input side
233
and the center point of symmetry
235
on the output side
237
.
FIG. 5
illustrates a small portion of the nozzle plate
211
that is positioned adjacent to the frame aperture
209
(not shown). Accordingly, the carrier frame
203
is not shown in FIG.
5
.
The tensile stress acting on the nozzle plate
211
is operative to symmetrically dispose the sidewall surfaces
219
about the nozzle axis
241
and to align the center point of symmetry
231
on the input side
233
with the center point of symmetry
235
on the output side
237
so that the NCA
245
is substantially 0.0 degrees and is coaxially aligned with the nozzle axis
241
. An alternative way of viewing the relationship between the NCA
245
and the nozzle axis
241
is that when the NCA
245
is 0.0 degrees, a camber line
247
is coaxially aligned with the nozzle axis
241
. The camber line extends from the center point of symmetry
231
on the input side
233
thru the center point of symmetry
235
on the output side
237
. Consequently, the taught nozzle plate
211
of the present invention has planar input
213
and output
215
surfaces that are parallel to each other as illustrated in FIG.
5
.
On the other hand, a dimpled nozzle plate or other deformities in the nozzle plate can result in misalignment between the nozzle axis
241
and the NCA
245
such that the center point of symmetry
235
on the output side
237
is not aligned with the center point of symmetry
231
on the input side
233
. Accordingly, the NCA
245
is not 0.0 degrees and the camber line
247
is not coaxially aligned with the nozzle axis
241
.
For instance,
FIG. 5
illustrates a first angular displacement between the center point of symmetry
231
on the input side
233
and the center point of symmetry
235
a
on the output side
237
. A camber line
247
a
results in a non-zero NCA of
245
a
. Similarly,
FIG. 5
illustrates a second angular displacement between the center point of symmetry
231
on the input side
233
and the center point of symmetry
235
b
on the output side
237
. A camber line
247
b
results in a non-zero NCA of
245
b
. Although
FIG. 5
illustrates the angular displacements in two-dimensions, it will be clear to one skilled in the art to which the present invention pertains that camber lines
247
a
and
247
b
and their respective NCA's of
245
a
and
245
b
define a cone half-angle about the nozzle axis
241
.
In one embodiment of the present invention, the NCA
247
deviates from coaxial alignment with the nozzle axis
241
by no more than about 1.0 degrees. For example, in
FIG. 5
, the NCA
245
a
would be out of alignment with the nozzle axis
241
by no more than about 1.0 degree. Similarly, the NCA
245
b
would be out of alignment with the nozzle axis
241
by no more than about 1.0 degrees.
Moreover, the NCA
247
can be effected by a thickness
220
as measured between the input
213
and output
215
surfaces of the nozzle plate
211
. If the nozzle plate
211
is too thin the NCA
247
can be coaxially misaligned with the nozzle axis
241
by more than 1.0 degrees. Conversely, the NCA
247
can be coaxially misaligned with the nozzle axis
241
by more than 1.0 degrees if the nozzle plate
211
is too thick.
In another embodiment of the present invention the nozzle plate
211
has a thickness
220
(shown in dashed line) from about 12.70 μm to about 152.40 μm, and more preferably from about 25.40 μm to about 127.00 μm.
The nozzle
217
of the present invention can be formed in the nozzle plate
211
by laser ablating the nozzle plate
211
to form a thru hole that extends between the input
213
and output
215
surfaces. Accordingly, the material selected for the nozzle plate
211
should be able to withstand laser ablation. After laser ablation of the nozzle plate, the nozzle
217
can have substantially vertical sidewall surfaces
219
a
as illustrated in FIG.
28
. Preferably, the nozzle
217
has converging sidewall surfaces
219
b
that converge in a direction toward the output side
237
of the nozzle
217
as illustrated in FIG.
29
. More preferably, the nozzle
217
has converging sidewall surfaces
219
c
that are arcuate in shape and converge in a direction toward the output side
237
of the nozzle
217
as illustrated in FIG.
30
.
FIG. 5
also illustrates the taught nozzle plate
211
to coupled to a substrate
300
that defines an ink jet print head
301
mounted to the input side
213
of the nozzle plate
211
by a barrier layer
303
. A firing chamber
305
is formed in the barrier layer
303
and the substrate
300
. The barrier layer
303
seals the firing chamber
305
to the input side
213
of the nozzle plate
211
so that the firing chamber
305
is in fluid communication with the nozzle
217
. A fluid channel
307
supplies ink (not shown) to the firing chamber
305
from an ink reservoir (not shown). The firing chamber
305
includes a firing element
309
disposed in the firing chamber
305
and having a firing axis
311
that is aligned with the nozzle axis
241
. A signal line
315
connects the firing element
309
to a control unit (not shown) that electrically communicates a signal to the firing element
309
. Those skilled in the ink jet printer art commonly refer to the firing element
309
as a thermal ink jet resistor; however, the term firing element will be used hereinafter. Furthermore, the firing element
309
is not to be construed as being limited to a thermal ink jet resistor. For instance, the firing element
309
can be a piezoelectric transducer.
As mentioned previously, the firing element
309
is operative to convert the ink supplied to the firing chamber
305
into an ink bubble
313
that is ejected from the firing chamber
305
along the firing axis
311
. The ink bubble
313
enters the input side
233
of the nozzle
217
and exits the nozzle
217
thru the output side
237
. As can be seen in
FIG. 5
, due to the taught nozzle plate
211
the NCA
245
is aligned with the nozzle axis
241
, therefore, the ink drop
313
will have a trajectory that substantially matches the NCA
245
. Resulting is improved accuracy in the directionality of the ink drop
313
such that the ink drop
313
travels along the camber line
247
with a trajectory that substantially matches the NCA
245
.
Referring to
FIG. 31
, a top plan view of the taught nozzle plate
211
(not shown) coupled to the ink jet printhead
301
of
FIG. 5
is shown. The firing axis
311
of the firing element
309
is in coaxially alignment with the input side
233
and the output side
237
of the nozzle
217
(not shown) so that ink ejected from the firing chamber
305
enters a true bore nozzle.
Another advantage of the taught nozzle plate
211
of the present invention is that the planar input surface
213
provides a flat and stable surface for mounting the printhead
301
. Consequently, voids and other defects in the barrier layer
303
that can be caused by dimples or other deformations in the input surface
213
are eliminated by the planar input surface
213
of the present invention. Moreover, a flat and stable input surface
213
for mounting the printhead
301
is operative to align the firing axis
311
of the firing element
309
with the nozzle axis
241
. If the nozzle
217
is not aligned with the firing axis
311
of the firing element
309
, then the ejected ink bubble
313
will not enter a true bore nozzle because the input side
233
of the nozzle
217
will be offset from the firing axis and the ink bubble will not travel along a symmetric path, thereby compromising ink drop directionality.
In one embodiment of the present invention, as illustrated in
FIGS. 23 and 25
, the chip carrier
201
includes an ink jet printhead
301
positioned in the frame aperture
209
and mounted to the input side
213
of the nozzle plate
211
by a barrier layer
303
that is disposed intermediate between the printhead
301
and the input surface
213
of the nozzle plate
211
.
The barrier layer
303
and the printhead
301
can have a firing chamber
305
formed therein (see FIG.
5
). The firing chamber
305
includes a firing element
309
disposed in the firing chamber
305
and a fluid channel
307
for communicating ink from an ink reservoir (not shown) to the firing chamber
305
. The firing chamber
305
is disposed adjacent to and in fluid communication with the input side
213
of the nozzle plate
211
. The firing chamber
305
is aligned with the nozzle
217
so that a firing axis
311
of the firing element
309
is coaxially aligned with the nozzle axis
241
.
The printhead
301
includes a signal line
315
that is in electrical communication with the firing element
309
. The firing element
309
is operative to eject an ink drop
313
in a direction along the firing axis
311
and into the nozzle
217
thru the input side
233
of the nozzle
217
in response to a signal from a control unit (not shown) that is in electrical communication with the signal line
315
. The term signal line as used herein includes a bonding pad, connector, or other electrically conductive connection disposed on the printhead
301
that electrically communicates the signal from the control unit to the firing element
309
.
Alignment of the firing axis
311
to the nozzle axis
241
can be accomplished by using a tool to move the chip carrier
201
and the printhead
301
(the assembly) relative to each other in μm increments until the firing axis
311
and the nozzle axis
241
are aligned. Additionally, alignment marks can be disposed on the nozzle plate to provide a reference point for the tool. Once aligned, the printhead
301
is pressed against the nozzle plate
211
followed by applying heat and pressure to the assembly to stake the printhead
301
to the nozzle plate
211
. The assembly is then placed in an oven at a high temperature to cure the barrier layer
303
.
In another embodiment of the present invention, as illustrated in
FIG. 22
, the chip carrier
201
includes a feed-thru aperture
401
extending between the input
213
and output
215
surfaces of the nozzle plate
211
. An electrically conductive trace
403
is disposed on the output surface
215
of the nozzle plate
211
. The trace
403
has a first end
405
that is in electrical communication with the control unit (not shown) and a second end
407
that is routed the feed-thru aperture
401
and is in electrical communication with the signal line
315
. The trace
403
is operative to electrically communicate the signal from the control unit to the signal line
315
. The feed-thru aperture
401
is positioned over the frame aperture
209
so that the signal line
315
is positioned adjacent to the feed-thru aperture
401
when the printhead
301
is mounted to the nozzle plate
211
as illustrated in FIG.
23
.
The trace
403
can be made from a material such as copper or gold plated copper, for example. Compression or ultrasonic TAB bonding can be used to connect the second end
407
to the signal line
315
. Referring to
FIG. 23
, with the ink jet printhead
301
positioned in the frame aperture
209
and mounted to the input surface
213
of the nozzle plate
211
, the second end
407
is routed thru the feed-thru aperture
401
and is connected to the signal line
315
. The signal line
315
can be a bonding pad, for example.
In one embodiment of the present invention, as illustrated in
FIGS. 24 and 25
, the chip carrier
201
includes a feed-thru aperture
401
extending between the input
213
and output
215
surfaces of the nozzle plate
211
. The carrier frame
203
includes an electrically conductive bonding pad
411
that is in electrical communication with the control unit (not shown). A bonding wire
413
is routed thru the feed-thru aperture
401
and is connected at a first end
415
to the bonding pad
411
and is connected at a second end
417
to the signal line
315
. The bonding wire
413
is operative to electrically communicate the signal from the control unit to the signal line
315
. The bonding wire
413
should be positioned as close as possible to the output surface
215
of the nozzle plate
211
so that the output side
237
of the nozzle
217
can be positioned as close as possible to the surface of a print media.
In another embodiment of the present invention, as illustrated in
FIG. 26
, the chip carrier
201
of
FIG. 23
or of
FIG. 25
is mounted to a print cartridge
601
. The print cartridge
601
has an enclosed volume that defines an ink reservoir
603
(shown in dashed outline). The base surface
207
of the carrier frame
203
is disposed on the print cartridge
601
and the frame aperture
209
is in fluid communication with the ink reservoir
603
so that ink
609
contained in the ink reservoir
603
is communicated to the ink jet printhead
301
thru the aperture frame
209
. The base surface
207
can be fixedly attached to the print cartridge
601
using an adhesive
611
, for example. The adhesive
611
should form a tight leak proof seal between the base surface
207
and the print cartridge
601
. An ink aperture
613
can be patterned in the adhesive
611
to allow the ink
609
to enter the frame aperture
209
.
It is desirable to separate the fluidic function of the nozzle plate
211
from the electronic function of the trace
403
or the bonding wire
413
. By removing signal lines from the output surface
205
of the nozzle plate
211
, the nozzle plate can be positioned closer to a surface to be printed, thereby reducing the distance the ink drop
313
must travel. Resulting is improved ink drop directionality. Furthermore, by separating the electrical function from the nozzle plate
211
the materials selected for the fluidic function of the nozzle plate
211
can be different than those selected for the electronic function.
Accordingly, in a preferred embodiment of the present invention, as illustrated in
FIG. 17
, a chip carrier
501
includes a carrier frame
203
A that is similar to the carrier frame
203
described above and illustrated in
FIGS. 9 and 13
; however, the carrier frame
203
A differs from the carrier frame
203
in that it includes an electrically conductive bonding pad
411
disposed on the carrier frame
203
A. Therefore, as discussed above, the chip carrier
501
includes the taught nozzle plate
211
disposed on the shelf surface
205
of the carrier frame
203
A with the input side
213
disposed adjacent to the frame aperture
209
of the carrier frame
203
A.
FIG. 16
is a top plan view of the carrier frame
203
A showing the nozzle plate
211
mounted on the shelf surface
205
. A plurality of the bonding pads
411
are shown; however, the carrier frame
203
A can have only one bonding pad
411
. The dimensions of the carrier frame
203
A can be larger than those of the carrier frame
203
in order to accommodate the extra surface area required by the bonding pad
411
. Suitable materials for the bonding pad
411
include copper and gold plated copper.
In the preferred embodiment, the chip carrier
501
separates the fluidic function of the nozzle plate
211
from the electronic function of the traces by including a flex circuit
503
as illustrated in FIG.
14
. The flex circuit
503
has opposed front
505
and back
507
surfaces and a nozzle aperture
509
that extends between the front surface
505
and the back surface
507
. The carrier frame
203
A is mounted to the back surface
507
so that the nozzle plate
211
is disposed in the nozzle aperture
509
as will be discussed below.
Referring to
FIG. 15
, in one embodiment the back surface
507
of the flex circuit
503
can include an electrically conductive trace
513
disposed on the back surface
507
. The trace
513
has a terminal end
515
and a finger end
517
. The terminal end
515
can be connected to a control unit (not shown) that electrically communicates print signals to an ink jet printhead (not shown) that is mounted to the carrier frame
203
A, for example. The finger end
513
connects with the bonding pad
411
as will be discussed below. Suitable materials for the trace
513
include copper and gold plated copper.
Referring to
FIG. 17
, the shelf surface
205
of the carrier frame
203
A is fixedly connected to the back surface
507
of the flex circuit
503
, thereby mounting the carrier frame
203
A to flex circuit
503
to form the chip carrier
501
. Glue or an adhesive, for example, can be used to fixedly connected the shelf surface
205
to the back surface
507
. Resulting is the nozzle plate
211
is disposed in the nozzle aperture
509
and the bonding pad
411
is positioned adjacent to the finger end
517
so that the finger end
517
of the trace
513
can be connected to the bonding pad
411
. The finger end
517
can be electrically connected to the bonding pad
411
using compression or ultrasonic TAB bonding, for example.
The material for the flex circuit
503
can be polyimide film, KAPTON™, UPILEX™, and APICAL™, for example. As mentioned above in reference to the carrier frame
203
and the nozzle plate
211
, the first material for the nozzle plate
211
can be polyimide film, KAPTON™, UPILEX™, and APICAL™, for example. Moreover, the second material for the carrier frame
203
A can be ceramic, alumina, nickel-iron alloy, KOVAR™, and INVAR™, for example.
Consequently, in the preferred embodiment, the flex circuit
503
can be made from UPILEX™ and the nozzle plate
211
can be made from a different material such as KAPTON™, for example. On the other hand, the flex circuit
503
and the nozzle plate
211
can be made from the same material. For instance, they both can be made from UPILEX™ or the both can be made from KAPTON™.
In the preferred embodiment, the nozzle plate
211
has the thickness
220
(see
FIG. 5
) from about 12.70 μm to about 152.40 μm, and more preferably from about 25.40 μm to about 127.00 μm.
As previously mentioned, the nozzle plate
211
is made from the first material having the first thermal expansion coefficient and the carrier frame
203
A is made from the second material having the second thermal expansion coefficient. The second thermal expansion coefficient of the carrier frame
203
A is less than the first thermal expansion coefficient of the nozzle plate
211
. The dissimilarity between the first and second thermal expansion coefficients is operative to generate the tensile stress on the nozzle plate
211
.
The first thermal expansion coefficient for the nozzle plate
211
is in a range from about 12.00 ppm/°C. to about 25.00 ppm/°C. The second thermal expansion coefficient for the carrier frame
203
A is in a range from about 3.00 ppm/°C. to about 11.00 ppm/°C.
The tensile stress on the nozzle plate
211
is in a range from about 6.50 Mpa to about 140.0 Mpa. The actual tensile stress acting on the nozzle plate
211
can vary with temperature. However, the above range represents the range of tensile stress at about room temperature.
The chip carrier
501
can include the lip
251
disposed on the shelf surface
205
with the nozzle plate
211
disposed on the planar upper surface
253
as illustrated in FIG.
18
. As discussed above the lip
251
provides a flat reference plane for the nozzle plate
211
.
The nozzle
217
can have converging sidewall surfaces
219
b
that converge in a direction toward the output side
237
of the nozzle
217
as illustrated in FIG.
29
. More preferably, the nozzle
217
has converging sidewall surfaces
219
c
that are arcuate in shape and converge in a direction toward the output side
237
of the nozzle
217
as illustrated in FIG.
30
. The NCA
247
of the nozzle
217
deviates from coaxial alignment with the nozzle axis
241
by no more than about 1.0 degrees (see FIG.
5
).
In one embodiment of the present invention, as illustrated in
FIGS. 19 and 20
, the chip carrier
501
includes an ink jet printhead
301
positioned in the frame aperture
209
and mounted to the input side
213
of the nozzle plate
211
by a barrier layer
303
that is disposed intermediate between the printhead
301
and the input surface
213
of the nozzle plate
211
.
The barrier layer
303
and the printhead
301
can have a firing chamber
305
formed therein (see FIG.
5
). The firing chamber
305
includes a firing element
309
disposed in the firing chamber
305
and a fluid channel
307
for communicating ink from an ink reservoir (not shown) to the firing chamber
305
. The firing chamber
305
is disposed adjacent to and in fluid communication with the input side
213
of the nozzle plate
211
. The firing chamber
305
is aligned with the nozzle
217
so that a firing axis
311
of the firing element
309
is coaxially aligned with the nozzle axis
241
.
The printhead
301
includes a signal line
315
that is in electrical communication with the firing element
309
. The firing element
309
is operative to eject an ink drop
313
in a direction along the firing axis
311
and into the nozzle
217
thru the input side
233
of the nozzle
217
in response to a signal from a control unit (not shown) that is in electrical communication with the signal line
315
. The term signal line as used herein includes a bonding pad, connector, or other electrically conductive connection disposed on the printhead
301
that electrically communicates the signal from the control unit to the firing element
309
.
In
FIG. 19
, a bonding wire
412
having first end in electrical communication with the bonding pad
411
and a second end in electrical communication with the signal line
315
. The bonding wire
412
is operative to communicate the signal present at the terminal end
515
of the trace
413
to the signal line
315
.
In one embodiment of the present invention, as illustrated in
FIG. 21
, the flex circuit
503
of the chip carrier
501
includes a feed-thru aperture that extends between the front surface
505
and the back surface
507
. A bonding wire
413
having a first end
415
connected to the bonding pad
411
and a second end
417
connected to the signal line
315
is routed through the feed-thru aperture
401
and is operative to electrically communicate the signal from the bonding pad
411
to the signal line
315
.
FIG. 20
is top view of the routing of the bonding wire
413
through the feed-thru aperture
401
of the flex circuit
503
.
In another embodiment of the present invention, as illustrated in
FIG. 27
, the chip carrier
501
of
FIG. 19
or of
FIG. 20
is mounted to a print cartridge
601
. The print cartridge
601
has an enclosed volume that defines an ink reservoir
603
(shown in dashed outline). The base surface
207
of the carrier frame
203
is disposed on the print cartridge
601
and the frame aperture
209
is in fluid communication with the ink reservoir
603
so that ink
609
contained in the ink reservoir
603
is communicated to the ink jet printhead
301
thru the aperture frame
209
. The base surface
207
can be fixedly attached to the print cartridge
601
using an adhesive
611
, for example. The adhesive
611
should form a tight leak proof seal between the base surface
207
and the print cartridge
601
. An ink aperture
613
can be patterned in the adhesive
611
to allow the ink
609
to enter the frame aperture
209
.
Although several embodiments of the present invention have been disclosed and illustrated, the invention is not limited to the specific forms or arrangements of parts so described and illustrated. The invention is only limited by the claims.
Claims
- 1. A chip carrier, comprising:a carrier frame having opposed shelf and base surfaces and a frame aperture extending between the opposed surfaces; a nozzle plate having opposed input and output surfaces and at least one nozzle formed by sidewall surfaces extending between the input and output surfaces, the nozzle has a nozzle camber angle measured relative to a nozzle axis and defined by an angular displacement between a center point of symmetry on an input side of the nozzle and a center point of symmetry on an output side of the nozzle, the nozzle plate is disposed on the shelf surface of the carrier frame with the input surface positioned adjacent to the frame aperture and the nozzle plate is fixedly connected to at least one pair of opposing sides of the shelf surface, the nozzle plate is characterized by being disposed on the shelf surface in a state of tensile stress so that the input and output surfaces of the nozzle plate are taught, planar, and parallel to each other, the tensile stress on the nozzle plate is operative to symmetrically dispose the sidewall surfaces of the nozzle about the nozzle axis and to align the center points of symmetry of the input and output sides of the nozzle with the nozzle axis so that the nozzle camber angle is substantially 0.0 degrees and is coaxially aligned with the nozzle axis, and wherein a fluid injected into the nozzle thru the input side exits the nozzle from the output side with a fluid trajectory that substantially matches the nozzle camber angle.
- 2. The chip carrier of claim 1, wherein the nozzle plate comprises a first material having a first thermal expansion coefficient and the carrier frame comprises a second material having a second thermal expansion coefficient,the second thermal expansion coefficient is less than the first thermal expansion coefficient, and wherein dissimilarity between the first and second thermal expansion coefficients is operative to generate the tensile stress on the nozzle plate.
- 3. The chip carrier of claim 2, wherein the first thermal expansion coefficient is in a range from about 12.00 ppm/°C. to about 25.00 ppm/°C. and the second thermal expansion coefficient is in a range from about 3.00 ppm/°C. to about 11.00 ppm/°C.
- 4. The chip carrier of claim 2, wherein the first material is a material selected from the group consisting of polyimide film, KAPTON, UPILEX, and APICAL, andthe second material is a material selected from the group consisting of ceramic, alumina, nickel-iron alloy, KOVAR, and INVAR.
- 5. The chip carrier of claim 1, wherein the nozzle has converging sidewall surfaces and the sidewall surfaces converge in a direction toward the output side of the nozzle.
- 6. The chip carrier of claim 5, wherein the converging sidewall surfaces are arcuate in shape.
- 7. The chip carrier of claim 1, wherein the nozzle plate has a thickness from about 12.70 μm to about 152.40 μm.
- 8. The chip carrier of claim 7, wherein the thickness of the nozzle plate is from about 25.40 μm to about 127.00 μm.
- 9. The chip carrier of claim 1, wherein the nozzle plate is fixedly connected to the shelf surface by an adhesive disposed intermediate between the shelf surface and the input surface of the nozzle plate.
- 10. The chip carrier of claim 1, wherein the shelf surface includes a raised portion defining a lip, the lip extends outward of the shelf surface and terminates in a planar upper surface,the input surface of the nozzle plate is disposed on the upper surface of the lip and the nozzle plate is fixedly connected to the shelf surface by an adhesive disposed intermediate between the shelf surface and the input surface of the nozzle plate, and wherein the lip is operative to provide a flat reference plane for the nozzle plate, whereby planarity of the nozzle plate is not compromised by non-uniform thickness of the adhesive.
- 11. The chip carrier of claim 1, wherein the nozzle camber angle deviates from coaxial alignment with the nozzle axis by no more than about 1.0 degrees.
- 12. The chip carrier of claim 1, wherein the tensile stress on the nozzle plate is in a range from about 6.50 Mpa to about 140.00 Mpa.
- 13. The chip carrier of claim 1, and further comprising:an ink jet printhead positioned in the frame aperture and mounted to the input surface of the nozzle plate by a barrier layer disposed intermediate between the ink jet printhead and the input surface of the nozzle plate.
- 14. The chip carrier of claim 13, wherein the barrier layer and the ink jet printhead have a firing chamber formed therein, andthe firing chamber includes a firing element disposed in the firing chamber and a fluid channel for communicating ink from an ink reservoir to the firing chamber, the firing chamber is disposed adjacent to and in fluid communication with the input side of the nozzle so that a firing axis of the firing element is coaxially aligned with the nozzle axis, the printhead includes a signal line in electrical communication with the firing element, and wherein the firing element is operative to eject an ink drop from the firing chamber in a direction along the firing axis and into the nozzle thru the input side of the nozzle in response to a signal from control unit in electrical communication with the signal line.
- 15. The chip carrier of claim 14 and further comprising:a feed-thru aperture extending between the input and output surfaces of the nozzle plate; an electrically conductive bonding pad disposed on the carrier frame and in electrical communication with the control unit; and a bonding wire, the bonding wire routed thru the feed-thru aperture and connected at a first end to the bonding pad and connected at a second end to the signal line, the bonding wire operative to electrically communicate the signal from the bonding pad to the signal line.
- 16. The chip carrier of claim 14 and further comprising:a feed-thru aperture extending between the input and output surfaces of the nozzle plate; and an electrically conductive trace disposed on the output surface of the nozzle plate, the trace having a first end in electrical communication with the control unit and a second end that is routed thru the feed-thru aperture and is in electrical communication with the signal line, the trace is operative to electrically communicate the signal from the control unit to the signal line.
- 17. The chip carrier of claim 13, wherein the carrier frame is mounted on a print cartridge having an enclosed volume that defines an ink reservoir,the base surface of the carrier frame is disposed on the print cartridge and the frame aperture is in fluid communication with the ink reservoir whereby ink contained in the reservoir is communicated to the ink jet printhead thru the frame aperture.
- 18. A chip carrier, comprising:a carrier frame having opposed shelf and base surfaces and a frame aperture extending between the opposed surfaces, the carrier frame includes an electrically conductive bonding pad disposed thereon; a flex circuit having opposed front and back surfaces and a nozzle aperture extending between the front and back surfaces; a nozzle plate having opposed input and output surfaces and at least one nozzle formed by sidewall surfaces extending between the input and output surfaces, the nozzle has a nozzle camber angle measured relative to a nozzle axis and defined by an angular displacement between a center point of symmetry on an input side of the nozzle and a center point of symmetry on an output side of the nozzle, the nozzle plate is disposed on the shelf surface of the carrier frame with the input surface positioned adjacent to the frame aperture and the nozzle plate is fixedly connected to at least one pair of opposing sides of the shelf surface, the nozzle plate is characterized by being disposed on the shelf surface in a state of tensile stress so that the input and output surfaces of the nozzle plate are taught, planar, and parallel to each other, the tensile stress on the nozzle plate is operative to symmetrically dispose the sidewall surfaces of the nozzle about the nozzle axis and to align the center points of symmetry of the input and output sides of the nozzle with the nozzle axis so that the nozzle camber angle is substantially 0.0 degrees and is coaxially aligned with the nozzle axis, wherein a fluid injected into the nozzle thru the input side exits the nozzle from the output side with a fluid trajectory that substantially matches the nozzle camber angle; and the shelf surface of the carrier frame is fixedly connected to the back surface of the flex circuit so that the nozzle plate is disposed in the nozzle aperture.
- 19. The chip carrier of claim 18, wherein the nozzle plate comprises a first material having a first thermal expansion coefficient and the carrier frame comprises a second material having a second thermal expansion coefficient,the second thermal expansion coefficient is less than the first thermal expansion coefficient, and wherein dissimilarity between the first and second thermal expansion coefficients is operative to generate the tensile stress on the nozzle plate.
- 20. The chip carrier of claim 19, wherein the first thermal expansion coefficient is in a range from about 12.00 ppm/°C. to about 25.00 ppm/°C. and the second thermal expansion coefficient is in a range from about 3.00 ppm/°C. to about 11.00 ppm°C.
- 21. The chip carrier of claim 19, wherein the first material is a material selected from the group consisting of polyimide film, KAPTON, UPILEX, and APICAL, andthe second material is a material selected from the group consisting of ceramic, alumina, nickel-iron alloy, KOVAR, and INVAR.
- 22. The chip carrier of claim 18, wherein the flex circuit is a material selected from the group consisting of polyimide film, KAPTON, UPILEX, and APICAL.
- 23. The chip carrier of claim 18, wherein the nozzle has converging sidewall surfaces and the sidewall surfaces converge in a direction toward the output side of the nozzle.
- 24. The chip carrier of claim 23, wherein the converging sidewall surfaces are arcuate in shape.
- 25. The chip carrier of claim 18, wherein the nozzle plate has a thickness from about 12.70 μm to about 152.40 μm.
- 26. The chip carrier of claim 25, wherein the thickness of the nozzle plate is from about 25.40 μm to about 127.00 μm.
- 27. The chip carrier of claim 18, wherein the nozzle plate is fixedly connected to the shelf surface by an adhesive disposed intermediate between the shelf surface and the input surface of the nozzle plate.
- 28. The chip carrier of claim 18, wherein the shelf surface includes a raised portion defining a lip, the lip extends outward of the shelf surface and terminates in a planar upper surface,the input surface of the nozzle plate is disposed on the upper surface of the lip and the nozzle plate is fixedly connected to the shelf surface by an adhesive disposed intermediate between the shelf surface and the input surface of the nozzle plate, and wherein the lip is operative to provide a flat reference plane for the nozzle plate, whereby planarity of the nozzle plate is not compromised by non-uniform thickness of the adhesive.
- 29. The chip carrier of claim 18, wherein the nozzle camber angle deviates from coaxial alignment with the nozzle axis by no more than about 1.0 degrees.
- 30. The chip carrier of claim 18, wherein the tensile stress on the nozzle plate is in a range from about 6.50 Mpa to about 140.00 Mpa.
- 31. The chip carrier of claim 18, and further comprising:an ink jet printhead positioned in the frame aperture and mounted to the input surface of the nozzle plate by a barrier layer disposed intermediate between the ink jet printhead and the input surface of the nozzle plate.
- 32. The chip carrier of claim 31, wherein the barrier layer and the ink jet printhead have a firing chamber formed therein, andthe firing chamber includes a firing element disposed in the firing chamber and a fluid channel for communicating ink from an ink reservoir to the firing chamber, the firing chamber is disposed adjacent to and in fluid communication with the input side of the nozzle so that a firing axis of the firing element is coaxially aligned with the nozzle axis, the printhead includes a signal line that is in electrical communication with the firing element and the bonding pad, and wherein the firing element is operative to eject an ink drop from the firing chamber in a direction along the firing axis and into the nozzle thru the input side of the nozzle in response to a signal from a control unit in electrical communication with the bonding pad.
- 33. The chip carrier of claim 32 and further comprising:an electrically conductive trace disposed on the back surface of the flex circuit, the trace having a terminal end in electrical communication with the control unit and a finger end that is in electrical communication with the bonding pad; and a bonding wire having a first end in electrical communication with the bonding pad and a second end in electrical communication with the signal line.
- 34. The chip carrier of claim 32 and further comprising:a feed-thru aperture extending between the front and back surfaces of the flex circuit; and a bonding wire, the bonding wire routed thru the feed-thru aperture and connected at a first end to the bonding pad and connected at a second end to the signal line, the bonding wire operative to electrically communicate the signal from the bonding pad to the signal line.
- 35. The chip carrier of claim 31, wherein the chip carrier is mounted on a print cartridge having an enclosed volume that defines an ink reservoir,the base surface of the carrier frame is disposed on the print cartridge and the frame aperture is in fluid communication with the ink reservoir whereby ink contained in the reservoir is communicated to the ink jet printhead thru the frame aperture.
US Referenced Citations (10)